Revert of Pass SequencedTaskRunner to PowerSaveBlocker for ui/file operations

content/browser/power_save_blocker_chromeos.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/power_save_blocker_impl.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "chromeos/dbus/power_policy_controller.h"
+#include "content/public/browser/browser_thread.h"
 
 namespace content {
 
 namespace {
 
 // Converts a PowerSaveBlocker::Reason to a
 // chromeos::PowerPolicyController::WakeLockReason.
 chromeos::PowerPolicyController::WakeLockReason GetWakeLockReason(
     PowerSaveBlocker::Reason reason) {
   switch (reason) {
     case PowerSaveBlocker::kReasonAudioPlayback:
       return chromeos::PowerPolicyController::REASON_AUDIO_PLAYBACK;
     case PowerSaveBlocker::kReasonVideoPlayback:
       return chromeos::PowerPolicyController::REASON_VIDEO_PLAYBACK;
     case PowerSaveBlocker::kReasonOther:
       return chromeos::PowerPolicyController::REASON_OTHER;
   }
   return chromeos::PowerPolicyController::REASON_OTHER;
 }
 
 }  // namespace
 
 class PowerSaveBlockerImpl::Delegate
     : public base::RefCountedThreadSafe<PowerSaveBlockerImpl::Delegate> {
  public:
   Delegate(PowerSaveBlockerType type,
            Reason reason,
-           const std::string& description,
-           scoped_refptr<base::SequencedTaskRunner> ui_task_runner)
-      : type_(type),
-        reason_(reason),
-        description_(description),
-        block_id_(0),
-        ui_task_runner_(ui_task_runner) {}
+           const std::string& description)
+      : type_(type), reason_(reason), description_(description), block_id_(0) {}
 
   void ApplyBlock() {
-    DCHECK(ui_task_runner_->RunsTasksOnCurrentThread());
+    DCHECK_CURRENTLY_ON(BrowserThread::UI);
     if (!chromeos::PowerPolicyController::IsInitialized())
       return;
 
     auto* controller = chromeos::PowerPolicyController::Get();
     switch (type_) {
       case kPowerSaveBlockPreventAppSuspension:
         block_id_ = controller->AddSystemWakeLock(GetWakeLockReason(reason_),
                                                   description_);
         break;
       case kPowerSaveBlockPreventDisplaySleep:
         block_id_ = controller->AddScreenWakeLock(GetWakeLockReason(reason_),
                                                   description_);
         break;
       default:
         NOTREACHED() << "Unhandled block type " << type_;
     }
   }
 
   void RemoveBlock() {
-    DCHECK(ui_task_runner_->RunsTasksOnCurrentThread());
+    DCHECK_CURRENTLY_ON(BrowserThread::UI);
     if (!chromeos::PowerPolicyController::IsInitialized())
       return;
 
     chromeos::PowerPolicyController::Get()->RemoveWakeLock(block_id_);
   }
 
  private:
   friend class base::RefCountedThreadSafe<Delegate>;
   virtual ~Delegate() {}
 
   PowerSaveBlockerType type_;
   Reason reason_;
   std::string description_;
 
   // ID corresponding to the block request in PowerPolicyController.
   int block_id_;
 
-  scoped_refptr<base::SequencedTaskRunner> ui_task_runner_;
-
   DISALLOW_COPY_AND_ASSIGN(Delegate);
 };
 
-PowerSaveBlockerImpl::PowerSaveBlockerImpl(
-    PowerSaveBlockerType type,
-    Reason reason,
-    const std::string& description,
-    scoped_refptr<base::SequencedTaskRunner> ui_task_runner,
-    scoped_refptr<base::SequencedTaskRunner> blocking_task_runner)
-    : delegate_(new Delegate(type, reason, description, ui_task_runner)),
-      ui_task_runner_(ui_task_runner),
-      blocking_task_runner_(blocking_task_runner) {
-  ui_task_runner_->PostTask(FROM_HERE,
-                            base::Bind(&Delegate::ApplyBlock, delegate_));
+PowerSaveBlockerImpl::PowerSaveBlockerImpl(PowerSaveBlockerType type,
+                                           Reason reason,
+                                           const std::string& description)
+    : delegate_(new Delegate(type, reason, description)) {
+  BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
+                          base::Bind(&Delegate::ApplyBlock, delegate_));
 }
 
 PowerSaveBlockerImpl::~PowerSaveBlockerImpl() {
-  ui_task_runner_->PostTask(FROM_HERE,
-                            base::Bind(&Delegate::RemoveBlock, delegate_));
+  BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
+                          base::Bind(&Delegate::RemoveBlock, delegate_));
 }
 
 }  // namespace content